Tag api documentation is here
Don’t forget about group tags you probably want to do it at the same time.
The way I would approach I would create some sort of reference table
Where I would say “this alias path this tag” i.e.
"root/news/" "news"
"root/news/corpo" "corporatenews"
And then iterate through this table getting documents by alias path and tagging them
It is more the question how you are going to use these tags later on.